Hanoi customs officials confiscated 19 pieces of suspected rhino horns weighing 2.15 kilograms on May 4, while another smaller batch of rhino horn was seized the same day by their Ho Chi Minh City counterparts.

Officials at Noi Bai International Airport at 3 p.m. found the contraband in the luggage of Nguyen Trung Dung, 24, and Pham Minh Chau, 28, both Hanoi residents, and Nguyen Thi Nguyet, 26, from Hung Yen, 64 kilometers from Hanoi.

They had arrived on a flight from Doha, Qatar, which had stopped over in Bangkok, Thailand.

None of them declared the horns with customs, and all failed to produce any papers authorizing their importation.

The airport's customs department detained Chau, Dung and Nguyet.

Experts said the confiscated horn pieces are worth billions of dong if they indeed come from rhinos.

HCMC customs officials on May 4 also seized two horns weighing a total of 7.28 kilograms wrapped in silver paper and hidden in the luggage of a 34-year-old Vietnamese named N.D.D., who arrived in the city on a flight from Doha.

D. has been detained pending an investigation.

Conservation groups at an international conference of 178-member Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) on wildlife conservation in March urged Vietnam to step up its efforts to crack down on the illegal trade of rhino horn.

Vietnam promised to do their best but also asked for support from other CITES member countries in the fight, according to news reports.

Last July, Vietnam objected to a ranking by the WWF which named it the worst in terms of wildlife protection among 23 African and Asian countries known for their high levels of poaching and trading in ivory, rhino horn and tiger parts.

Conservationists say the country has taken several steps to deal with the illegal wildlife trade.